No Passive Solar Heat (for now)

I wanted to mention the issue of passive solar, since I've had so many inquiries into "are we planning to do passive solar". Yes. We are planning passive solar, as well as a pv array eventually. The pv array will be expensive up front, and since the budget wont support it at this time, we're putting that off for at least a few years. Eventually, we do want to be on pv, with the grid as merely a backup source for electricity.
As far as passive solar for heated water (including heat for our radiant floor), that's going to be a year or two after the house is built. Here's way:
I spent a considerable amount of time working with a vendor in Tulsa that markets passive solar water heaters. Typically, the put them on the roofs of houses. It seemed like a good idea to me, and I liked the product I saw (I first saw them at a local home&garden exhibit).However, after spending all that time with them, explaining that this was an earth home, and that our annual ambient temperature wasn't going to deviate that much, and that I'd only need enough btu to raise the temperature about 10 degrees (Fahrenheit), and probably not even that, they came back with a bid for nearly $30,000.
$30,000!!!! ?????
I couldn't believe it. The thing is, the salesman assured me that "their engineer" had calculated it out, and based on the square footage of our house, this is what it would take.
"Square footage". That was a key phrase. I realized, that just like almost every vendor, craftsman, etc that we've dealt with in the building process, they assume you're stupid and you don't know what you're talking about, and they have these books and formulas that they've been given (books written by engineers and formulas put together by engineers).As it turns out, their "engineer" wasn't an engineer at all. He was just a relatively smart guy that could use the formulas and calculate what was needed. Either the salesman didn't give him the information that I gave, or the guy didn't realize that the information I provided would affect the formulas and that they needed to take that into account.
Those formulas are based on annual temperatures for the region, plus the average heat loss (or gain) for the average (traditionally built) house. An earth home or otherwise energy efficient house like our's, would not match with that data. Without new data (that I provided) the formulas wouldn't provide the answers for our home.
After explaining this to the salesman, and working out one of the formulas myself, I saw his eyes glaze over. I realized that I was going to get nowhere with him.
Rather than be impolite or rude, or nasty (like I was tempted to be), I decided to smile, shake his hand and thank him for his time (despite the fact that he wasted a tremendous amount of my time), and left.
I figure that at some point in the future, after the house is built and we're living in it, I'll return to the topic of passive solar.I might even build my own panels and forget those guys. Or maybe by then, there'll be some competition in the area and I might have better luck with another company.As it is, I'm confident that I can build a passive solar air-based heater that can provide heated air through the house, and take colder air in the exchange (to be reheated). These types of heaters are fairly easy to build and there are plenty of designs on the internet that are free. The thing is, the air doesn't retain the heat as long as the liquid in a radiant floor would, but I'm not going to worry about that at this time. Eventually, the radiant floor will have warm water going through it keeping it warm (and the air above it as well).
It could turn out, that we wont need much heat. Jerry told me that when he was growing up, they only heated their house with a wood stove (like the one we have now), and it heated a house bigger than the one we're building. And he said that they didn't burn wood all the time.
Considering that they lived in the Kansas City area and we're further south, it seems to me that our heating needs wont be as great.So I'm willing to wait to see what we're really going to need.
I still plan on putting the pex tubing in the slab, so that it'll be there if we really feel we need radiant floor heating. Putting it in ahead of time isn't nearly as expensive as trying to retrofit (which would be cost prohibitive).